Severe, harsh (10)
I believe the answer is:
astringent
I believe this clue is a double definition.
'severe' is the first definition.
(I've seen this before)
'harsh' is the second definition.
(harsh can mean astringent or severe)
(Other definitions for astringent that I've seen before include "Harsh" , "Lotion" , "Styptic" , "(Of taste) sharp, bitter" , "(Medication) causing contraction - stern giant (anag)" .)